Every year, 6,000 killers get away with murder in the US. Police fail to make an arrest in more than a third of all homicides and the majority of homicides now go unsolved at dozens of big-city police departments, according to a Scripps Howard News Service study of crime records provided by the FBI and reported in The Journal Gazette. According to the article, murders have become tougher to solve because there are fewer crimes of passion and more gang-related killings.